bazel | Bazel WORKSPACE , BUILD , and .bzl configs | Build Tool library

I tried to build and run a Qt5 (5.15.2) application on macOS (10.15.7) using Bazel 5.0.0. Unfortunately, I run into some problems. The building part seems to work, but not the run part.

I installed Qt5 on my machine using Homebrew:

I'm working on a C++ project and I need Numpy like arrays and functionalities in C++. I found some alternatives like xtensor, NumCpp etc. These are header only libraries. The problem is I'm experimenting with Bazel for the first time so, I don't have any idea about how do I add header only library to Bazel workspace. There are some suggestions like genrule-environment, rules-foreign-cc suggested on other questions around Bazel. I've added http_archive to WORKSPACE file, but I'm not sure what to add in BUILD file.

WORKSPACE file

I'm using bazel to run a go test on my CI system. The go test will need to use a helper binary built from another go file.

The dir structure looks like the following:

Is there a way that I can use a Bazel-based library like for example lyra inside a CMake-based project? Example: I have a simple hello world program, which is built using CMake - can I somehow use CMake to automatically build the Bazel library and link it somehow in my CMake project so that I can use the lyra library in the main file?

Let me start by saying I'm new to Bazel. I am trying to build a Docker container from a golang project that contains local module references.

First I'm creating a local golang module:

Is there a way to do this? I'm trying to build parts of the AWS SDK (s3 and rds) to use in my Bazel project. I've heard that rules_foreign_cc can be used to integrate CMake projects with Bazel.

I'm interested in seeing if bazel ran in the recent past. Where can I find general logging for past bazel build/run/fetch (maybe somewhere in /var/log)?

I am randomly getting the following error when I am executing the binary (sometime it works):

Been reading the Bazel docs over and over to the point where nothing feels new, but I cannot seem to grasp how to setup configurations and variants for variants other than the native ones, e.g. --cpu and --compilation_mode.

To explain what I mean with configuration and variants, consider this table of Configuration rows, and Variant Points columns, and Variant cells (making this table up, hope it at least makes abstract sense):

From a Bazel user perspective:

• All targets should be buildable for all configurations by default
  • Not ok adding "Customer configuration X" everywhere on adding a configuration
  • Configuration specific components should be possible to explicitly state which configuration it is specific to
    • I think this is what constraint_value is for
• Rules should add flags based on configuration
  • For example -DVARIANT_POINT_CONNECTED_ETH for Ethernet connection and -DVARIANT_POINT_CONNECTED_USB for USB connection
• I want a simple build command for building/testing/running a single configuration
  • Something like bazel build //my/target --//:configuration=debughw
  • Think there is something about it in the skylark config docs, but not seeing how to go from the example to using constraint_values and select() in rules